yaole
43 lines
1.2 KiB
Go
43 lines
1.2 KiB
Go
package sm2a
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import (
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"math/big"
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"xdx.jelly/xgcl/gmath"
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"xdx.jelly/xgcl/sm/sm2"
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)
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type ClientDecContext struct {
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cipher *sm2.Cipher
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}
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func NewClientDecContext() *ClientDecContext {
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return &ClientDecContext{
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cipher: sm2.NewCipher(),
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}
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}
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// Decrypt_one 客户端协同解密第一步，输出cipher.C1并发送给服务端
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func (c *ClientDecContext) Decrypt_one(cipher *sm2.Cipher) ([]byte, error) {
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out := make([]byte, 0, 2*sm2.ByteSize())
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cipher.X.Mod(cipher.X, sm2.OrderN())
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cipher.Y.Mod(cipher.Y, sm2.OrderN())
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out = append(out, gmath.BigIntToNByte(cipher.X, sm2.ByteSize())...)
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out = append(out, gmath.BigIntToNByte(cipher.Y, sm2.ByteSize())...)
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c.cipher.Set(cipher)
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return out, nil
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}
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// Decrypt_two 客户端协同解密第二步，收到服务端计算结果 [d_s]·C1,计算解密明文。
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func (c *ClientDecContext) Decrypt_two(in []byte, dc *sm2.PrivateKey) ([]byte, error) {
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x := new(big.Int)
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y := new(big.Int)
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x.SetBytes(in[:sm2.ByteSize()])
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y.SetBytes(in[sm2.ByteSize() : 2*sm2.ByteSize()])
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xx, yy := sm2.Curve256.ScalarMult(c.cipher.X, c.cipher.Y, dc.D.Bytes())
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x, y = sm2.Curve256.Add(x, y, xx, yy)
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// (x,y) = d*C1, 后续解密同标准SM2解密一致
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return sm2.Decrypt_aux(x, y, c.cipher)
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}
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